This invention relates to a method and apparatus for building a tire including storing strip material, such as tire tread or sidewalls after extrusion and before application to an unvulcanized tire without deforming the strip material while it is being transported and is in storage.
Heretofore, strip material for building a tire has been carried on a liner and stored on a spool with the individual layers of liner separating the individual layers of strip material. The weight of the outer layers of the strip material was carried by the inner layers of strip material and has deformed the inner layers. This has been especially undesirable when the strip material had a predetermined cross sectional profile shape, as in the case of a tread or sidewall of a tire.
It has been proposed in Japanese Patent A 61111261 to coil a liner in spiral slots of the flanges of a winding spool and during the winding of the liner feeding an extruded tire sidewall into the pocket between the layers of the liner to prevent deformation of the sidewall. In order to guide the liner into the spiral slots, the liner was reduced in width by pulling it through a carved former. This precluded using the liner to transport the sidewall into or out of the spool. Accordingly, the sidewall was not provided with any support from an extruder spaced from the spool to a position within the spool on the coiled liner. This is not desirable because it permits stretching and uncontrolled deformation of the sidewall between the extruder and the spool. Uncontrolled stretching of the sidewall is also a problem during transporting of the sidewall from the spool to a conveyor during unloading of the spool. This is especially a problem with other strip components for tires where uniformity of the strip components is necessary to provide tires which meet the high standards required at this time.
The present invention provides for storing and transporting a strip component in a spool having a hub and flanges with spiral grooves on the inner faces of the flanges. Edges of a liner are pulled into the spiral grooves in the flanges of the spool and the liner coils form a pocket in which the strip material is supported and protected. The edges of the liner maintain the liner coils in spaced relation so that the strip material is not compressed or deformed. The liner is made of a material which is stiff enough to support the strip material when it is suspended between the interfaces of the flanges and has sufficient resiliency so that the edges can bend and spring into the spiral grooves of the flanges during winding of the liner on the spool. This resilience of the liner permits removal of the liner edges from the spiral grooves as it is unwound from the spool. By supporting the liner in a coiled configuration in the grooved flanges of the spool, the liner is held in the shape of a hoop which provides increased strength to support the strip material.
Guides are provided to engage the edges of the liner before it enters the spool for bending the edges of the liner in a direction normal to the line of travel of the liner and urging the edges into the spiral grooves. The guides do not obstruct the passage of the liner into the pocket of the spool and therefore the liner may be utilized to support and transport the strip material from an extruder or other strip forming apparatus to the spool in a supported condition. This is highly desirable to maintain the shape and dimensions of the strip material especially when it is still in a heated condition. The liner may also be used to support and transport the strip material during unloading of the spool.
According to an aspect of the invention, there is provided a method of storing strip material in a spool without compressing portions of the strip material underlying other portions of the strip material comprising:
a. attaching a first end of a liner to the spool, the spool having spaced-apart flanges with spiral grooves in the axially inward opposing surfaces of the flanges for receiving edges of the liner,
b. wrapping a second end of the liner around a liner storage spool, characterized by;
c. depositing the strip material on the liner,
d. guiding the edges of the liner into the spiral grooves forming spaced-apart coils while carrying the strip material into space between said coils.
According to another aspect of the invention, there is provided apparatus for loading and storing strip material in a spool rotatably mounted on a supporting structure, the spool comprising a generally cylindrical core having axially outer ends and an axis, first and second flanges having an axially inner surface and an axially outer surface, and being fixedly attached to one of the axially outer ends of the core and each inner surface having a spiral groove extending radially outwardly from a radially inward starting point on each of the flanges near an interface of the core and the flanges, an elastically deformable liner having elastically deformable edges characterized by a pair of guide rods positioned adjacent each inner surface for engagement with the edges to selectively guide the edges into the grooves providing an unobstructed center portion of the liner for carrying the strip material into the spaces between overlapping convolutions of the liner.